Tapping device for generating periodic mechanical pulses

ABSTRACT

A tapping device for attachment to apparatus to impart periodic mechanical pulses thereto comprises a base adapted to be secured to the apparatus, an electromagnet mounted on the base and comprising a ferro-magnetic core and a winding, an anvil projecting up from the base at one side of the electromagnet and an armature support projecting up from the base at the opposite slide of the electromagnet. An armature extending across the top of the electromagnet has one end disposed above the anvil and the opposite end pivotally supported by the support. A spring acts on the armature to swing it away from the electromagnet while a screw extending through a hole in the armature and screwed into the core limits such movement. An electrical circuit periodically energizes the electromagnet to attract the armature and cause the armature to strike the anvil, thereby generating a mechanical pulse which is transmitted through the anvil and base to the apparatus on which the tapping device is mounted.



1. A tapping device to be mounted on apparatus for imparting periodic mechanical pulses thereto, comprising a base for attachment to said apparatus, and electromagnet on said base and comprising a ferromagnetic core perpendicular to the base and a winding around said core, an anvil projecting from said base at one side of said electromagnet and parallel to said core, armature supporting means projecting from said base at the opposite side of said electromagnet from said anvil, an armature extending across said electromagnet from said supporting means to said anvil, said anvil having a first end disposed above said anvil and a second end pivotally supported by said supporting means for movement of said armature between a first position in which said first end of the armature engages said anvil and a second position in which said first end of said armature is spaced from said anvil, means biasing said armature in a direction from said first position to said second position, means limiting movement of said armature in said direction, and circuit means for periodically energizing said electromagnet at regular fractional-second intervals to attract said armature and thereby cause said first end of said armature to strike said anvil to generate a mechanical pulse which is transmitted through said base to apparatus on which said tapping device is mounted.
 2. A tapping device according to claim 1, in which said means limiting movement of the armature comprises a screw extending through a hole in the armature and screwed adjustably in a central tapped hole in said core, said screw having a head forming a stop for said armature.
 3. A tapping device according to claim 2, further comprises a ring of elastomeric material surrounding said screw below the head and engageable by said armature to prevent metal-to-metal contact between said armature and the head of said screw.
 4. A tapping device according to claim 1, in which said anvil and said armature supporting means are integral with said base.
 5. A tapping device according to claim 4, in which said base, anvil and armature supporting means comprise a single metal stamping.
 6. A tapping device according to claim 1, in which said base, anvil armature supporting means and core comprise a single sintered powdered metal molding.
 7. A tapping device according to claim 1, in which said armature supporting means comprises two posts projecting up from said base, said armature having said second end portion disposed between said posts and pivotally supported by a pin extending through aligned openings in said posts and armature.
 8. A tapping device according to claim 7, in which said biasing means comprises a tension spring acting between said second end portion of said armature and a pin extending between said posts.
 9. A tapping device according to claim 1, in which a pad of elastomeric material between said armature and said anvil prevents metal-to-metal contact between said armature and said anvil.
 10. A tapping device according to claim 9, in which said pad comprises a cap of elastomeric material fitting on the upper end of said anvil. 